A cargo deck of an aircraft usually has roller conveyors on which items of freight, particularly containers, can be moved particularly in the aircraft's longitudinal direction. The containers then also stand on these roller conveyors during the flight, where locking bars that engage with (standardized) sections of the containers are normally provided.
A significant problem with such roller conveyors is that on one hand high stability and ruggedness must be met, as operation frequently takes place under difficult conditions and nevertheless has to run smoothly, while on the other the weight of such roller conveyors represents a significant problem. Finally, there is also a problem in that the loading possibilities must be highly variable. In order to guarantee this, it must be possible to travel over the roller conveyors, and particularly the roller conveyors installed centrally in the aircraft's cargo hold, with them lying centrally under a container as necessary, and in the case of other container dimensions with them functioning on only the peripheral sides under a container thus supporting it.